Nonmetallic spring for upholstery



Feb. 4, 1947. SCHAEFER 2,415,374

NONMETALLIC SPRING FOR UPHOLSTERY Filed Oct. 20, 1943 INVEN TOR.

.JY/JTUSJ'SCHHEFER HTTORNEY Patented Feb. 4, 1947 UNITED STATES PATENT OFFICE NONMETALLIC SPRING FOR UPHOLSTERY Justus J. Schaefer, Great Barrington, Mass.

Claims. 1

This invention'relates to furniture and upholstery, and more particularly to an interior coiled spring made from vulcanized fiber or other similar material which is especially adapted to be used in innerspring mattresses, spring cushions, and other upholstered furniture.

One object of this invention is to provide a coiled spring of the above nature which may be made from a sheet of highly compressed vulcanized fiber or other suitable non-metallic material by a process which comprises first cutting up said sheet into a plurality of strips of square cross section, grinding said strips into circular cross section, soaking the rods formed. thereby in a cold salt water solution, twisting said rods in one direction, and finally drawing said twisted rods through a heated spring-forming die in the opposite direction.

A further object is to provide a coiled sprin of vulcanized fiber composition, in which a basefiller of shredded canvas has been added to said composition.

A further object is to provide a spring of the above nature, in which the final coiled rod, by reason of the twisting and coiling which it has received during the process of manufacture, will permanently maintain its original resiliency, strength, pitch, and length without unwinding during use.

A further object is to provide a spring of the above nature, in which a final coating of waterproof varnish has been applied after the spring has emerged from the forming die.

Aestill further object is to provide a coiled spring of the above nature, which will be simple in construction, inexpensive to manufacture, easy to install and manipulate, compact, ornamental in appearance, rustless, noiseless, nonbreakable, non-conductive to electricity, unaffected by heat or cold, and very eflicient and durable in use.

With these and other objects in view there have been illustrated on the accompanying drawing two forms in which the invention may conveniently be embodied in practice.

In the drawing,

Fig. 1 represents a perspective view of a sheet of highly compressed vulcanized fiber prior to being cut up into a plurality of straight strips of square cross section along the lines indicated.

Fig. 2 is a perspective view of one of the cut strips indicated in Fig. 1, which is shown at the left as square in cross section, and at the right as round in cross section after it has been reduced to a circular rod of the desired size by a grinding wheel also illustrated.

App ication October 20, 1943, Serial No. 506,994

Fig. 3 is a sectional view of a tank containing a cold salt water solution, and showing a vulcanized fiber rod in the bottom thereof being treated by said solution.

Fig. 4 is a perspective view on a larger scale of a vulcanized fiber rod after the next step of twisting it counterclockwise.

Fig. 5 is a diagrammatic view showing another step in the first process of manufacturing the coiled spring, which consists in passing the twisted rod shown in Fig. 4 through a heated springforming die in a clockwise direction, and showing the protective varnish coating which is applied to the rod after it has passed through said die.

Referring now to the drawing in which like reference numerals denote corresponding parts throughout the several views, the numeral l9 indicates generally a rectangular elongated sheet of highly-compressed vulcanized fiber having shredded canvas incorporated therein which is adapted to be cut into strips H of square cross section, as indicated by the lines l2 shown in Fig. 1. At the left of Fig. 2, one of the square strips H is shown passing to the right (as indicated by the arrow) into engagement with a grinding wheel it which serves to remove the longitudinal edges from the square strip H for converting it into a rod M of circular or round cross section, as shown at the right of said figure.

The next step in the first process of producing the spring stock, is to place one of the rods [4 in an elongated tank l5 containing a cold one per cent solution of salt water I6, as shown in Fig. 3, and to soak said rod in the salt water bath for about twelve hours to harden, toughen, and solidify it.

The rod 14 is then removed from the tank [5, dried, and twisted in a counter-clockwise direction to increase the stiffness strength and resiliency thereofsaid twist being indicated by the helical line H in Fig. 4.

The twisted rod M will then be passed through a clockwise spring-forming die 48, (as shown in Fig. 5), which is preferably heated to a high temperature, causingthe rod Hi to assume an open helical coil shape l9 as indicated at the right of said figure.

The final step in the process of forming the coiled spring is to apply a coating 28 of a phenolic resin varnish or other similar material to the rod M, which will permit the spring to thereafter be bent repeatedly without injury to said coating.

In the present application, the term vulcanized fiber refers to any commercial type of this material, which may be reddish-brown, gray, black, or any other color, and of horny consistency. This material is oil proof, quite resistant to chemical action and organic solvents. It is also ductile, non-brittle and elastic. Generally, it has a tensile strength of from 8,000 to 13,000 lbs. per square inch, and a crushing strength of from 35,000 to 45,000 lbs. per square inch. Vulcanized fiber is commonly produced by running unsized unloaded rag paper through a warm solution of zinc chloride to cause it to soften and become plastic, winding upon a roll until the desired thickness is obtained, cutting off a sheet of material and washing until all traces of the zinc chloride are removed. The resultant sheet is then subjected to compression and hardening in a press.

While there have been disclosed in this specification several forms in which the invention may be embodied, it is to be understood that these forms are shown for the purpose of illustration only, and applicant does not desire to be limited to the specific disclosure, except as required by the following claims:

Having thus fully described the invention, what is claimed as new, and for. which it is desired to secure Letters Patent, is: Y

1. In an upholstery spring, a helical coil of highly compressed vulcanized fiber stock, said stock being twisted throughout its length on its own axis to increase thestrength, stifiness and resiliency thereof and impregnated with sodium chloride to increase thetoughness thereof.

2. In an upholstery spring, a helical coil of highly compressed vulcanized fiber stock having a'filler of shredded canvas incorporated therewith, the stock of said coil being twisted throughout its length on its own axis to increase the strength, stiffness, and resiliency thereof and to prevent said coil from unwinding or stretching during use.

'3. In an upholstery spring, a coil of highly compressed solidified plastic fibrous vulcanized fiber composition having ductile, non-brittle, elastic properties, the stock of said coil being twisted throughout its length on its own axis to 4 increase the strength, stiifness and resiliency thereof.

4.'In an upholstery spring, a helical coil of highly compressed vulcanized fiber, the stock of said coil being twisted throughout its length on its own axis to increase the strength, stifiness, and resiliency thereof and to prevent said coil from unwinding or stretching during use.

5. In an upholstery spring, a resilient coil of solidified hardened plastic composition of vulcanized fiber having a reinforced filler of fibrous material embedded therein, the stock of said coil being twisted throughout its length to increase the strength, stifiness, and resiliency thereof.

JUSTUS J. SCHAEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 71,169 Hayward Nov. 19, 1867 116,557 Cobb July 4, 1871 2,171,095 Orsini Aug. 29, 1939 50,622 Payne Oct. 24, 1865 99,475 Rhinelander Feb. 1, 1870 101,957 Willard Apr. 12, 1870 122,001 Eagleton Dec. 19, 1871 170,973 Tyler Dec. 14, 1875 2,110,029 Shastock Mar. 1, 1938 2,098,082 Bowen, et al. Nov. 2, 1937 2,171,890 Precourt Sept. 5, 1939 2,363,826 1 Yellin m. Nov. 28, 194% 1,824,220 Mackey Sept. 22, 1931 FOREIGN PATENTS Number Country Date 37,754 German Dec. 9, 1886 OTHER REFERENCES Plastics Catalog (pg. 715-716) 1943-Pub. in 1942 by Plastics Cat. Corp. N. Y.--Copy in Division 50. 

